Modified Gate Diffusion Input Technique: A New Technique for Enhancing Performance in Full Adder Circuits

Abstract

Addition is an indispensable operation for any high speed digital system, digital signal processing or control system. The primary issues in the design of adder cell are area, delay and power dissipation. Optimization of several devices for speed and power is a significant issue in low-voltage and low-power applications. These issues can be overcome by incorporating Gated Diffusion Input (GDI) technique. This paper mainly presents the design of 5 different full adder topologies using Modified Gate Diffusion Input Technique. This technique allows reducing power consumption, delay and area of digital circuits, while maintaining low complexity of logic design. This paper focuses two main design approaches. The former presents the implementation of modified primitive logic cells and its performance issues were compared with GDI and CMOS logic. The latter presents the implementation of 5 different modified GDI full adders and its performance issues. The simulation results reveal better delay and power performance for the proposed modified GDI full adders when compared with the existing GDI technique, CMOS and pass transistor logic at 0.250μm CMOS technologies. Delay and power has been evaluated by Tanner simulator using TSMC BSIM 0.250μm technologies.